Signatures compressing when saving to SharePoint online library

Steps to reproduce:

- User has PDF's saved in a SharePoint online library.

- They open the PDF in the browser from the library

- Click the sign and fill option and select their signature (a scanned image)

- Drop the signature on the page

- It appears correctly until the document is saved

- After saving the signature distorts and compresses to 1/4 its horizontal size

Issue does not occur for other users or in the acrobat desktop application (however user does not wish to use the desktop app for the extra clicks to add a signature.

Issue does occur for the same user in other document libraries, but not for other users saving in the same document library.